Intelligent and adaptive control system and method for wood burning stove

ABSTRACT

A control system and method for a wood stove adjustably operates in accordance with operational characteristics of the wood stove. The system operates air vents to the combustion chamber of the stove to control operating temperatures of the stove. The air vents are adjusted proportionally to changes in temperature of the stove. The temperature of the stove may be controlled to achieve desired operational and burn characteristics. The system further includes a heat exchange fan. The system controls the speed of the heat exchange fan based upon the operational characteristics of the stove.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to controllers for wood burning stoves orfurnaces. More particularly, it relates to an intelligent and adaptivewood combustion controller for adjusting combustion airflow and heattransfer airflow for improved performance.

2. Discussion of Related Art

Control of a wood stove can be complex and difficult. Typically, a woodstove includes a number of manual controls for controlling thecombustion and heat transfer processes. The controls can be difficult toset and must be adjusted periodically to keep the fire in the stoveburning well and to provide heat from the stove to the surrounding area.Typically, a wood stove includes two types of controls. A first type ofcontrol provides air to the combustion process. The amount of airavailable for combustion determines the strength of the fire. Incompletecombustion results from too little air. However, too much air will leadto overheating the stove, leading to excessive draft, making it nearlyimpossible to limit the combustion. Furthermore, the amount of air whichis too much or too little depends upon the amount of fuel in the stove,the current temperature of the fire, and length of time the fire hasbeen burning. In order to keep a fire operating at the desiredperformance, the draft air flow must be adjusted repeatedly during thecombustion process.

Typically, a wood stove installed in a fireplace opening will include afan or fans causing air to pass around the combustion chamber to provideheated air to the room. The speed of the heat exchange fan controls theamount of heat extracted from the fire and provided to the room. To getmore heat into the room, the speed of the fan is increased. Furthermore,the speed of the fan also has an effect on the combustion process. Asmore air is forced through the stove, it removes more heat from thecombustion process. Although a faster speed fan allows heat to transfermore quickly into a room, it also will reduce the temperature of theinner wall and the fire itself, reducing the draft air supplying thefire. If too much heat is removed through the heat transfer process, thefire may overcool and burn poorly.

Various mechanisms have been devised to automate parts of the controlprocesses for wood stoves. Such mechanisms typically include athermostat or similar device for determining the temperature of thestove or the room. The level of combustion air and the speed of the heatexchange fan are adjusted to maintain a desired temperature. However,such systems do not account for differences in the operation of a firewith respect to time or offer variations in operating modes. Throughimproved control, the stove can be operated more efficiently, providingsuperior heating characteristics and convenience to the user.

SUMMARY OF THE INVENTION

According to one aspect, the present invention includes a system forcontrolling operation of a wood stove. The system monitors thetemperature of the stove over time. Air vents to the combustion chamberserve as a draft air control and are adjusted based upon temperaturechanges. According to another aspect of the invention, the systemadjusts the air vents to achieve desired operational characteristics forthe wood stove. According to aspects of the invention, the air vents areadjusted to achieve one of a maximum burn time for a fire, a maximumheat output, a maximum efficiency, or ambient room temperature control.According to other aspects of the invention, the system adjustsautomatically to achieve desired operation of the wood stove. The systemmonitors operation of the stove and adjusts the air vents in accordancewith the desired performance of the stove.

According to another aspect of the invention, the system includes atraining mode for learning operational performance of the wood stove.The system monitors the temperature and air vent openings periodicallyduring manual operation of the wood stove. The system uses informationgenerated during the training mode for controlling the air vents duringautomatic operation of the wood stove.

According to another aspect of the invention, the system can control aheat exchange fan on the wood stove. The speed of the heat exchange fanis adjusted based upon the temperature of the stove, the operation ofstove, and desired operational characteristics for the stove.

According to another aspect of the invention, a method for operation ofa wood stove is based upon operational characteristics of the wood stoveand performance of the stove. According the method, air vents areproportionally adjusted based upon changes in temperature of the stove.According to another aspect of the invention, the method the air ventsare adjusted based upon rates of temperature change. According toanother aspect of the invention, the method includes control of a heatexchange fan based upon operational characteristics of the stove.According to another aspect of the invention, the method controls thestove to achieve a desired operation for the wood stove. Desiredoperations include maximum burn time with a quiet fan (Mode 1), maximumheating efficiency with moderate fan speed (Mode 2), maximum heatingefficiency with high fan speed (Mode 3), maximum heat output with amaximized fan speed and shorter burn time (Mode 4), and ambient roomtemperature control (Mode 5).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front view of a wood stove and controller according to anembodiment of the present invention.

FIG. 2 is a cross sectional view of the wood stove of FIG. 1.

FIG. 3 is a graph of temperature of a wood stove showing varioustemperature profiles depending upon a selected operating mode.

FIG. 4 is a graph for the vent opening calculated according to thetemperature profile in FIG. 3 and the selected operating mode.

FIG. 5 is a graph of the fan speed calculated according to thetemperature profile in FIG. 3 and the selected operating mode.

DETAILED DESCRIPTION

The present invention 1 provides a controller for improved performanceof a wood stove. FIG. 1 illustrates a typical configuration of a woodstove 10 to which the controller of the present invention may beapplied. The wood stove 10 is of typical construction. It includes acombustion chamber 20 in which wood is burned. A door (not shown)operates to allow wood to be placed within the combustion chamber 20 ofthe wood stove 10. According to current governmental regulations, thedoor provides an airtight seal to separate the combustion chamber 20from the surrounding air of the stove. A flue 15 is connected to thecombustion chamber 20 to allow smoke and gases to exit the combustionchamber 20.

The stove 10 further includes a pair of spaced apart walls 22, 23. Aninner wall 22 surrounds the combustion chamber 20. An outer wall 23surrounds the inner wall. A heat transfer space 31 is formed between thetwo walls 22, 23. FIG. 2 is a cross sectional view of the stove. Itillustrates the heat transfer space 31. A fan 30 is connected to thewood stove 10 and operates to force air into the heat transfer space 31between the walls. The fan operates to pass air from the areasurrounding the stove into the heat transfer space 31. A set of openings32 in an upper front portion of the outer wall 23 provides an exitlocation for air being forced into the heat transfer space 31. Duringoperation of the wood stove 10, the combustion chamber 20 and inner wall22 are heated from the combustion process. The air within the heattransfer space 31 is heated through contact with the inner wall 22. Theair is then forced from the heat transfer space 31 to heat the areaaround the stove 10. The airflow within the heat transfer space 31 isillustrated in FIG. 2.

A set of vents 24 provide an opening to the combustion chamber forcontrol of draft air. As combustion occurs, smoke, heat and air areexhausted through the chimney. This causes a draft, which pull airthrough the vents 24 into the combustion chamber. Sufficient air isnecessary for combustion. The amount of air available can be controlledby the opening of the vents 24 or by a damper on the chimney, whichcontrols the amount exhausted. While the present invention is describedwith respect to control of vents, it may also include control of adamper. Additionally, a fan can be used to force air into the combustionchamber. Any of these mechanisms control the amount of air in thecombustion chamber which is available for combustion and constitutecontrol of the draft air.

The vents 24 include closures (not shown) for adjusting the opening sizeof the vents 24. With the vents open, more air is available in thecombustion chamber 20 for the combustion process. The amount of airavailable controls the combustion process. According to an embodiment ofthe present invention, the vents are controlled with anelectromechanical servo-controlled actuator. The actuator is connectedto vents so that the vents can be opened and closed through signalsprovided to the actuator. A low-cost, commonly available, off-the-shelfactuator typically used for radio controlled airplanes, cars, boats andother toys can be used for the actuator.

FIGS. 1 and 2 illustrate a known configuration of a wood stove to whichthe controller of the present invention can be applied. However, thepresent invention is not limited to such a construction. It may be usedwith any wood stove or furnace which allows control of draft air and/orheat transfer air.

The present invention further includes a controller 40 for controllingoperation of the fan 30 and the vents 24 in a manner to achieve desiredperformance. Preferably, the controller 40 includes a microprocessor orother device for receiving inputs (as discussed below) and provideoutputs to control the stove. A non-volatile memory is connected to themicroprocessor. The memory includes a program executable by themicroprocessor to perform the control desired with respect to thepresent invention. The memory is capable of being reprogrammed with anupdated program to improve performance further or to add new features.

A thermocouple 41 or similar device is connected to the stove. Asillustrated in FIG. 1, the thermocouple 41 may be connected to the innerwall 22 to provide an accurate temperature of the stove. Alternatively,the thermocouple 41 could be attached to the outer wall 23 to provide amore accurate temperature reading or to another location in the room.More than one thermocouple can be used to provide temperatures atdifferent locations throughout the room to allow different kinds ofcontrol.

The controller 40 is connected to the thermocouple 41 to receive aninput regarding the temperature of the fire and/or room. The controlleruses the information regarding temperature 40 to control the opening ofthe vents 24 and the speed of the heat transfer fan 30 to achievedesired results. One advantage of the present invention is theflexibility provided by the controller 40. The flexibility is providedby the programming of the controller. Under prior art systems, a currenttemperature is used to control operation of the wood stove. Theprogrammable controller of the present invention allows the history andcondition of the fire to be used, in connection with the currenttemperature to provide control. This allows more complete control to beprovided.

FIG. 3 illustrates a typical temperature profile for a wood stove overtime. When started, the fire takes some time for the wood to dry and tobegin producing heat. It then has a fairly constant high temperaturelevel for a period of time. As the fuel supply begins to be exhausted,the temperature starts to drop off. The amount of air needed forcombustion, illustrated in FIG. 4, depends not only on the temperatureof the fire, but also on the rate of change of the temperature and theposition of the fire within the combustion cycle illustrated in FIG. 3.Similarly, the speed of the air passing through the heat transfer space31 to achieve desired performance will also depend upon the combustioncycle. FIG. 5 illustrates a desired fan velocity profile in connectionwith the combustion cycle in FIG. 3. The controller of the presentinvention uses the temperature of the stove, obtained from thethermocouple 41, in connection with programming relating to priortemperatures, desired performance or operation of the stove, and currentchanges in temperatures to provide the necessary control.

Operational characteristics of the controller are discussed below. Theseonly represent examples of how the controller of the present inventionmay be operated. Other programming can be used for providing differentoperations for the controller to achieve different results for controlof the stove.

The controller monitors the temperature of the stove and adjusts thevents as necessary to control the fire. When a fire is started, the userwill press a button on the controller to indicate a start in the firemonitoring process. The controller will fully open the vents. Thecontroller monitors the temperature until a threshold temperature isexceeded. When the threshold is reached, the controller waits apredetermined time, typically one minute, and checks the temperatureagain. If the temperature has risen, then the vents are closed by anamount that is proportional to the temperature rise. If the temperatureis unchanged, the vents remain the same. If the temperature drops, thevents are opened an amount proportional to the change in temperature inorder to restore combustion. The wait, check and adjust process is thencontinuously repeated until the temperature of the fire falls below athreshold. While control of the vents is described as being proportionalto the temperature rise, the present invention does not require just alinear relationship. The proportional relationship may depend upon otherfactors, such as the absolute temperature. Since the controller isprogrammable, multiple factors can be used to determine the desiredopening level for the vents.

According to an embodiment of the present invention, the adjustmentsmade to the vent openings by the controller can be varied based upondesired operational characteristics of the stove. Upon starting a fire,the user selects a desired type of operation. Adjustments to the ventsare made in order to meet the objectives of the type of operation. Theuser may change the desired type of operation at any time duringoperation. The objective of the control algorithm under any type ofoperation is to maintain the efficient burn of the fire and maintain aconsistent volume of draft air to the fire as the temperature increasessuch that the stove temperature reaches an acceptable peak temperature,rather than overheating and burning up all the fuel prematurely, orsmoldering and producing little heat. The different types of operationdepend upon the desired rate of temperature increase and peaktemperature. According to a preferred embodiment of the invention,several different types of operation are possible:

In a first type of operation, Mode 1, a maximum burn time is desired.The objective is to utilize the fire to heat the house as long aspossible. Burn time is maximized in order to keep from overheating ahome. It can also be used to extend the time that the fire will last sothat it does not require monitoring, such as overnight or when the homeis unoccupied for a period of time. A lower temperature and heat outputare accepted in order to extend the burn time. The stove is kept at alow temperature with a restricted vent setting. In this mode, the ventsare closed more than in the other modes of operation as the stove heatsup. When the maximum desired temperature is reached, the vents areadjusted in order to maintain that temperature.

The second type of operation is maximum heat. The objective of thisoperation is to get as much heat as possible from the stove in a shortperiod of time. It may be used when the home is cold and needs to beheated quickly. Heat output is maximized with a shorter burn time byincreasing the air supply and allowing a higher peak temperature.Combustion efficiency may be reduced to extract as much heat as possiblein a short period of time.

The third type of operation is likely to be the most common. Itsobjective is to maximize heating efficiency of the stove. Efficiency ismaximized to realize a maximum heat extraction from the fire relative tothe fuel consumed. In this condition, the stove peak temperature islimited to a moderate temperature.

In addition to the different automatic operational modes, the controllerallows a manual mode of operation. In this mode, the controller 40 makesno adjustments to the vent openings. The user may adjust the openingsmanually as desired. However, the controller 40 continues to monitoroperation of the stove in order to prevent problems due to undesirableoperation. There is a risk that the user will forget the draft aircontrol, leaving it fully open, creating a condition where the stovebecomes hotter than it should. To protect against this happening, thecontroller will monitor for an “over-temperature” condition in which thetemperature of the stove exceeds a preset temperature. If theover-temperature condition exists, the controller 40 will override themanual mode to limit the stove temperature. Specifically, the controllerwill fully close the vents. Once the temperature has been reduced to amore normal threshold, the vents will be returned to the prior manualsetting. Alternatively, the controller may close the vents to a levelless than fully closed in order to reduce the temperature of the stove.

Combinations of manual and automatic modes of operation can also be usedto provide greater flexibility for the user. While the controller is inthe automatic mode, the user may open or close the vents. A switch onthe controller can be used for manual operation of the vent openings.Once the user has changed the vent openings, the automatic mode cancontinue with the new opening level as the baseline for the currentconditions. Thus, the user can adjust the temperature without having tochange to a completely different operational mode.

In addition to controlling operation of the vents, according to anembodiment of the present invention, the controller can provideself-calibration processes to ensure proper operation in connection withdifferent stoves, actuators, thermocouples and other components.

According to one embodiment of the invention, the vent openings can becalibrated. In this process, the controller moves the draft control toeach extreme of its travel while monitoring the electrical currentfeeding the servo actuator or a position feedback signal. When the draftcontrol reaches the limit of its travel, the servo actuator motor willstall, and the current will increase significantly. The controller willdetect the increased current and identify the travel limit. The travellimits are then stored in non-volatile memory and retrieved after thecontroller has been turned off. The travel limits are used to determinethe amount of adjustment necessary during operation of the system. Fornew installations, the controller will initially begin with defaultsettings which will be restricted after calibration has succeeded. Inthe event of a mal-adjusted mechanical linkage where the draft controllimits are not reached, or the range of travel is insufficient, thecontroller will post an error message to the LCD display, insisting on amechanical adjustment and recalibration.

According to another embodiment of the invention, the servo currentcharacterization is calibrated. To account for variability between servoactuators, the controller characterizes the change in current drawbetween stalled and non-stalled conditions and calculates a thresholdfor determining whether the actuator motor stalled.

According to another embodiment of the invention, the servo actuatorprovides a feedback signal to the controller. This feedback signalserves to inform the controller of the position of the vent. This isimportant so that if the user grasps the vent control and moves it, thecontroller will be able to detect the change in position and actaccordingly. Additionally, if a mechanical problem develops and inhibitsthe vent control from moving, the controller will be able to detect thisand issue an audible alert signal.

According to another embodiment of the invention, the controller willtrack it's fire control performance and adaptively adjust its internalcontrol parameters such that the draft air control changes are scaled toavoid either stifling the fire, or allowing it to become excessivelyhot. This is important because the draft air supply is dependent uponthe exterior ambient air temperature. When the outside air is very cold,there will be a greater amount of draft available, requiring a largerdegree of closure as the stove temperature rises. Conversely, when theoutside air is warmer, there will be a less amount of draft air supply,requiring a smaller degree of closure as the stove temperature rises.

According to another embodiment of the invention, the controller willinclude an exterior temperature sensor which will provide a directmeasurement of exterior ambient temperature and enable the controller todirectly calculate the proper control parameters for the currentconditions.

According to another embodiment of the invention, the controllercalibrates to the thermocouple amplifier gain. To account forvariability between thermocouple and thermocouple amplifier gains, thecontroller gathers data to learn the desired operation. The controllercan be taught through manual operation of the stove. During a trainingphase, typically the first fire during which the controller is used, thecontroller monitors the temperature of the fire and the manualadjustments to the vents made by the user. This allows the system toaccount for differences in stoves and in desired conditions.Furthermore, the controller will have preset temperature thresholds todefine when the draft air control should be adjusted. The presetthresholds are used if the training has not occurred.

According to another embodiment of the invention, a small fan ispositioned at the vents 24 to force additional air into the combustionchamber. Current air-tight, high efficiency wood stoves operate veryefficiently when they have reached a proper operating temperature.However, prior to reaching an optimum operating temperature andconsequently adequate draft air, they may lack the ability to burnproperly. The door to the combustion chamber is often left slightly ajarby the user to permit additional air to enter the chamber. When a fireis started, the controller will activate the fan to provide additionalair to the combustion chamber. This eliminates the need to leave thedoor slightly open. The fan is disabled after the combustion chambertemperature has reached a temperature threshold. Of course, the fan canbe used at any time during operation of the stove to provide additionalcontrol for the draft air.

The system of the present invention includes various power monitoringand control capabilities. The draft control is closed upon theoccurrence of a power loss. The controller also saves the currentoperating state in non-volatile memory for recovery when power isrestored. In order to allow for power loss control, the controllerhardware includes a super-capacitor which stores enough energy tomaintain control long enough to close the draft air control. Thesuper-capacitor acts like a small rechargeable battery, yet without thereliability, cost and size issues associated with a NI-CAD battery pack.

During operation, the microprocessor constantly monitors the powersupply voltage. If the AC power is lost, the microcontroller immediatelydetects this and takes several measures:

a. Posts a “POWER LOSS” message to the LCD display

b. Stores the current operating state in non-volatile memory,particularly the current stove temperature and the position of the draftair control.

c. Closes the draft air control.

d. Waits to see if the power is restored.

e. If the power is restored while the microcontroller is still running,then it will return the draft air control to the prior setting andreturn to normal operation.

f. If the power is restored after the microcontroller shuts down, thenthe controller will read the stove temperature from memory and comparethis against the current stove temperature. If the two temperatures areclose together, then the damper control will be returned to the settingstored in memory. If the current temperature is very low, suggestingthat there is no longer any fire, then the damper is closed. If thecurrent temperature is significantly lower than the temperature frommemory, but high enough to indicate a remaining fire, then the damperwill be fully opened to attempt to restore the fire and resume heating.

According to another embodiment of the present invention, anuninterruptible power feature may be provided that maintains full powerand control for a duration of hours or days to support remoteinstallations where power losses are common. This uninterruptible powersupply may consist of small batteries, rechargeable or otherwise, thatcontinue operation until such time as power is restored. In the event ofextended operation and such time that battery power becomes reduced, thecontroller will sense the low power condition and post a message to theLCD display. If the battery power becomes critically low, then thesystem will shut down as described above.

According to another embodiment of the present invention, the controllerdetermines when more fuel is required and activates an alert. As thecontroller monitors the temperature of the stove, eventually all fuelwill be consumed, requiring additional wood to be added. When thetemperature reaches a predetermined level, which cannot be increasedthrough draft air control, an audible alert is activated to inform theuser that the fire has declined to the proper point where wood should beadded.

In addition to control draft air, the controller of the presentinvention adjusts the heat transfer fan base upon the desired operation.According to a preferred embodiment, the draft air and circulating fanare controlled jointly to achieve the desired operating characteristics.In automatic mode (independent of the selected operation), thecontroller adjusts the circulation fan(s) in proportion to the stovetemperature. As the temperature increases or drops, the speed of thecirculating fan will be adjusted similarly. The level of adjustment tothe fan will depend upon the operating mode of the system. In themaximum burn mode, the fan will be kept at a low speed in order tominimize fan noise. In the maximum heat transfer mode, the fan isoperated at the maximum fan speed once operating temperature has beenreached. In the maximum efficiency mode, the fan is operated at a middlelevel.

As with operation of the draft air control, in manual mode, the fanspeed is specified by the user. If the stove reaches an over-temperaturecondition, the controller will override the manual mode and set the fansto maximum speed until the temperature drops. Once the temperature hasreached a desired operating temperature again, the fan will be returnedto the manually set level.

According to another embodiment of the invention, the controllerprovides an alert for an extreme over-temperature condition. If thetemperature of the stove exceeds an extreme threshold level, even withthe over-temperature adjustments, it is likely that a mechanical failureexists. In such event, the controller will activate an audible alarm sothe user can address the problem immediately. With added electroniccontrols, the controller can be programmed to call a pager or cell phoneunder this condition to provide an alert to a user who is not present atthe home.

According to another embodiment of the invention, the controllerincludes electronic controls to keep track of the time, and in such casewhere the operating mode and temperature defines that the fan should beset at a high speed, but user-defined time settings have specified anoverriding “Quiet Time”, the controller will maintain a slower speed toreduce ambient fan noise until such Quiet Time has expired, whereuponthe controller will reset the fan to such higher speed as required bythe current temperature and operating mode. This Quiet Time may consistof a range of times whereupon the controller must operate quietlybetween the two times, or a single specification of a time durationbeginning with the present time.

In addition to controlling operation of the stove, according to anembodiment of the invention, the controller maintains a log of operationof the stove. The controller logs temperature measurements, draft aircontrol settings, and circulation fan speeds in non-volatile memory,such as an EEPROM. A computer interface allows the data from the memoryto be downloaded to a computer for review and analysis. The computerinterface may also be used to adjust the thresholds for greater controlof operation of the stove.

Having disclosed at least one embodiment of the present invention,various adaptations, modifications, additions, and improvements will bereadily apparent to those of ordinary skill in the art. Suchadaptations, modifications, additions and improvements are consideredpart of the invention which is only limited by the several claimsattached hereto.

1. A method for controlling operation of a wood stove having at leastone adjustable vent for controlling an amount of air entering acombustion chamber of the wood stove and at least one temperaturesensor, the method comprising the steps of: determining a change intemperature; and adjusting the at least one adjustable vent based uponthe change in temperature.
 2. The method for controlling operation of awood stove according to claim 1, wherein an extent of adjustment of theadjustable vent is proportional to the change in temperature.
 3. Themethod for controlling operation of a wood stove according to claim 1,wherein an extent of adjustment of the adjustable vent depends upon arate of temperature change.
 4. The method for controlling operation of awood stove according to claim 1, further comprising the step ofreceiving an input representing an operational mode for the wood stove;and wherein an extent of adjustment of the adjustable vent depends uponthe an operational mode for the wood stove.
 5. The method forcontrolling operation of a wood stove according to claim 4, wherein theoperational mode includes at one of a maximum burn time mode, a maximumheat output mode, and a heating efficiency mode.
 6. The method forcontrolling operation of a wood stove according to claim 1, furthercomprising the steps of: determining a rate of temperature change for avent opening level; and wherein the adjusting step includes adjustingthe at least one adjustable vent based upon the rate of temperaturechange.
 7. The method for controlling operation of a wood stoveaccording to claim 1, wherein the adjusting step includes adjusting theat least one adjustable vent based upon an external temperature.
 8. Themethod for controlling operation of a wood stove according to claim 1,further comprising the steps of: determining temperature of the woodstove at periodic intervals during manual operation of the stove;determining vent opening levels for the at least one adjustable vent atthe periodic intervals during manual operation of the stove; storing thedetermined temperature and vent opening levels; and wherein theadjusting step includes adjusting the at least one adjustable vent basedupon the stored determined temperatures and vent opening levels.
 9. Themethod for controlling operation of a wood stove according to claim 1,further comprising the step of forcing air into the combustion chamberof the wood stove based upon the change in temperature.
 10. The methodfor controlling operation of a wood stove according to claim 1, whereinthe wood stove includes a fan for moving air to transfer heat from thestove to a room, the method further comprising the step of: adjusting aspeed of the fan based upon the change in temperature.
 11. The methodfor controlling operation of a wood stove according to claim 10, whereinthe speed of the fan is adjusted based upon a selected mode of operationof the wood stove.
 12. A method for controlling operation of a woodstove having a fan for moving air to transfer heat from the stove to aroom and at least one temperature sensor, the method comprising thesteps of: determining a change in temperature; and adjusting a speed ofthe fan based upon the change in temperature.
 13. The method forcontrolling operation of a wood stove according to claim 12, furthercomprising the step of receiving an input representing a operationalmode for the wood stove; and wherein an extent of adjustment of theadjustable vent depends upon the an operational mode for the wood stove.14. A system for controlling a wood stove having at least one adjustablevent for controlling an amount of air entering a combustion chamber ofthe wood stove, the system comprising: a temperature sensor for sensinga temperature of the wood stove; a actuator connected to the at leastone adjustable vent for changing an opening of the at least oneadjustable vent; and a programmable controller connected to thetemperature sensor and the actuator for controlling the actuator basedupon an output from the temperature sensor and operationalcharacteristics of the wood stove.
 15. The system for controlling a woodstove according to claim 14, wherein the programmable controllerincludes a training mode for determining operational characteristics ofthe wood stove.
 16. The system for controlling a wood stove according toclaim 14, further comprising: a external temperature sensor for sensingan external air temperature connected to the programmable controller;and wherein the programmable controller controls the actuator based uponan output from the external sensor.
 17. The system for controlling awood stove according to claim 14, wherein the programmable controllerincludes an input representing a desired operational mode of the woodstove.
 18. The system for controlling a wood stove according to claim14, wherein the wood stove includes a fan for moving air to transferheat from the stove to a room, the system further comprising: a secondactuator connected to the programmable controller for controlling aspeed of the fan; and wherein the programmable controller controls thesecond actuator based upon the output from the temperature sensor andthe operational characteristics of the wood stove.
 19. A method forcontrolling operation of a wood stove having at least one adjustablevent for controlling an amount of air entering the combustion chamber ofthe wood stove and at least one temperature sensor, the methodcomprising the steps of: selecting a operational mode; sensing atemperature of the wood stove; determining an opening level of the atleast one adjustable vent based upon the selected operational mode andthe sensed temperature; and adjusting the at least one adjustable ventto the determined opening level.
 20. A method for controlling operationof a wood stove having at least one adjustable vent for controlling anamount of air entering the combustion chamber of the wood stove and atleast one temperature sensor, the method comprising the steps of: duringa first operational mode: sensing changes to an opening level of the atleast one adjustable vent made by a user of the wood stove; sensing atemperature when a change in the opening level of the at least oneadjustable vent is sensed; and storing the temperature level and openinglevel; and during a second operational mode: sensing a temperaturelevel; and adjusting an opening level of the at least one adjustablevent based upon the sensed temperature level and the stored temperaturelevel and opening level.